In quadrilateral ABCD, ∠D = 40°, ∠C = 80° AP bisects angle A and BP bisects angle ∠B; then ∠APB is equal:

1. 90°

2. 120°

3. 90°

4. 60°

The sum of interior angles of a polygon is 900°. The number of side in this polygon is:

1. 5

2. 7

3. 9

4. 11

Find the number of sides ina polygon if the sum of its interior angles is 16 right angles.

Is it possible to have a polygon whose sum of interior angles is:

(i) 870°

(ii) 2340°

(iii) 7 right angles ?